Vehicle speed-limiting apparatus

ABSTRACT

A governing apparatus for a double barrel compound type carburetor including a mechanism to open the primary throttle thereof which comprises a servo device to open the secondary throttle of the carburetor in accordance with venturi vacuum produced at least within the primary induction passage and an external vacuum source communicated therein and to close the secondary throttle by biasing force of a spring installed therein when vehicle speed exceeds a predetermined value, thereby to prevent excessive vehicle speeds.

United States Patent 1 191 1111 3,756,209

Hida et a1. Sept. 4, 1973 [54] VEHICLE SPEED-LIMITING APPARATUS 3,596,642 8/1971 Nakata 123/l03 R 3,521,609 7/1970 Kashiwa iet a1... 123/117 A [751 Invelltors: Takash lfhda; f Sakaklba"? 3,502,167 3/1970 Baxter"? 123 103 R Nflbllyllkl Hashim"), all of Karlya, 2,620,783 12 1952 Lee 123 103 R Japan [73] Assignee: Aisin Seiki Kabushiki Kaisha, Primary ExaminerAl Lawrence Smith Kariya-shi, Aichi-ken, Japan Assistant Examiner-Dennis Toth 221 Filed: Feb. 18, 1972 Mama-Mommy Kjima 211 Appl. No.: 227,380

[57] ABSTRACT [30] Foreign Application Priorit D t A governing apparatus for a double barrel compound Feb 20 1971 Japan 46/81 10 type carburetor including a mechanism to open the primary throttle thereof which comprises a servo device 52 U.S. c1. 123/103 A 123/127 sewndary the caburemr 51 lm. F020 11/08 codance with vent vacuum Pwdmd east Within [58] Field of Search 123/103 R 109 110 the Primary inductim Passag'a an enema vacuum 12371 17 A ,108 source communicated therein and to close the secondary throttle by biasing force of a spring installed therein [56] References Cited when vehicle speed exceeds a predetermined value,

UNTED STATES PATENTS thereby to prevent excessive vehicle speeds.

3,021,827 2/1962 Brunner 123/127 8 Claims, 4 Drawing Figures GOVERNOR SHEEI 1 OF 3 PATENTEDSEP 4 '91s ZQ. MAN/F OLD VACUUM GOVERNOR PAIENTEnscr 4am 3.756209 SHEET 2 BF 3 Fig 3 l! 1 I5 22 MAN/F OLD VACUUM 0 I6 I I7 20 I2 PATENTED SEP 4 I973 SHEEI 3 BF 3 Bl MAN/FOLD VACUUM GOVERNOR VEHICLE SPEED-LIMITING APPARATUS BACKGROUND OF THE INVENTION The present invention relates to a speed-limiting mechanism for a vehicle, or more particularly to a governing apparatus to control a compound type carburetor for preventing excessive vehicle speeds.

SUMMARY OF THE INVENTION The prime object of the present invention is to provide a governing apparatus for a double-barrel compound type carburetor for preventing excessive vehicle speeds without causing any bad effect to the primary carburetor, thereby to provide smooth and satisfactory vehicle speedlimiting control with simple and partial improvement or reconstruction of the carburetor.

Another object of the present invention is to provide a governing apparatus for a double-barrel compound type carburetor, having the above-mentioned features, wherein the governing apparatus controls only the secondary throttle of the carburetor and the primary throttle, or the carburetor as a whole, remains operative in case the governing apparatus goes out of order.

Yet another object of the present invention is to provide a governing apparatus for a double-barrel compound type carburetor, having the above-mentioned features, wherein until the vehicle speed reaches a predetermined value, the governing apparatus is operative to open the secondary throttle by venturi vacuum force produced within the primary induction passage and engine manifold vacuum force, and is operated to close the secondary throttle by return force of resilient means installed therein when the vehicle speed exceeds the predetermined value, thereby to enable sequential throttle control.

Still another object of the present invention is to provide a governing apparatus for a double-barrel compound type carburetor, having the above-mentioned features, wherein the governing apparatus is operated by venturi vacuum force produced both in the primary and secondary induction passages and engine manifold vacuum force so as to open the secondary throttle as long as vehicle speed remains below a predetermined value, and is regulated by return force of resilient means installed therein in response to venturi vacuum force within the secondary induction passage so as to close the secondary throttle when the vehicle speed exceeds the predetermined value, thereby to enable precise sequential throttle control.

A further object of the present invention is to provide a governing apparatus for a double-barrel compound type carburetor, wherein at and around a predetermined speed of the vehicle, the governing apparatus conducts preliminary fine adjusting operation so as to smoothly control engine operation.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, features and advantages of the present invention will become more readily apparent from the following description of the preferred embodiment with reference to the accompanying drawings forming a part of the specification.

In the drawings:

FIGS. 1, 2 and 3 show elevational sectional views of a governing apparatus in accordance with the present invention respectively; FIG. 1 illustrating the governing apparatus in inoperative condition, FIG. 2 showing the governing apparatus in operative condition until the vehicle speed reaches a predetermined value, and FIG. 3 depicting the governing apparatus in operative condition at and over the predetermined speed of the vehicle.

FIG. 4 shows an elevational sectional view of a modified embodiment of the present invention, being conditioned in inoperative state.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawing, there is shown a preferred embodiment in accordance with the present invention adapted onto a well known double-barrel compound type carburetor 10. The carburetor 10 comprises a first induction passage 33 of the primary throttle and a second induction passage 11 of the secondary throttle. Throttle valves 34 and 12 are pivotally mounted respectively within the first induction passage 33 and the second induction passage 11.

The first throttle valve 34 is to be opened in accordance with operator demand as manifested by accelerator pedal position. When the open degree of the first throttle valve 34 exceeds a given value, the second throttle valve 12 is mechanically opened by 2 4 by way of a conventional type link device (not shown) so as to prevent stick of the valve 12 to the second induction passage wall. Then, the open degree of the second throttle valve 12 is automatically controlled by a link or control rod 18 actuated by a servo device indicated generally at reference numeral 15. The servo device 15 includes a casing 31 which peripherally clamps a first and a second diaphragm members 17 and 19 therein. The casing 31 and the first diaphragm member 17 form a chamber 20 which is vented to the atmosphere by way of a conduit 22 and is connected to a solenoid operated valve 24, which will be described hereinafter, through a branch circuit 23. The casing 31 and the second diaphragm member 19 form a chamber 21 which is in connection with the solenoid valve 24 through a conduit 25. Thus, the chamber 21 is selectively connected to the engine r'nanifold vacuum force or the atmosphere by way of operation of the solenoid valve 24 through a conduit 29 or the conduits 23 and 22. A chamber 16 is formed inbetween the two diaphragm members 17 and 19 to be supplied with venturi vacuum force through a conduit 14 and vacuum bleeders 13 opening to the primary and secondary induction passages 33 and 11. The servo device 15 further includes a coiled return spring 26 stretched between the two diaphragm members 17 and 19, and :a coiled compression spring 32 mounted at one end on the inner wall of the casing 31 and at the other end on .a stopper 30 secured on the second diaphragm member 19. The first spring 26 has a larger biasing force than that of the second spring 32. The stopper 30 is urged onto the inner wall of the casing 31 while the chamber 21 is communicated with the engine manifold vacuum.

The solenoid valve 24 is to switch-over connection of the chamber 21 to the atmosphere from the manifold vacuum when the vehicle speed exceeds a given value. The solenoid valve 24 is operated by a solenoid 27 which is energized by electric signals generated from a well known centrifugal governor 40.

Described below is the operation of the aboveexplained preferred embodiment of the present invention.

When engine rotation increases with the vehicle speed slower than the predetermined one, air-induction resistance at the primary throttle increases only to decrease engine torque. At the same time, however, venturi vacuum force delivered into the chamber 16 from the vacuum bleeders 13 and engine manifold vacuum force into the chamber 21 increase to cause right-andupward displacement of the diaphragm members 17 and 19 against biasing force of the springs 26 and 32 as illustrated well in FIG. 2. Thus, opening degree of the throttle valve 12 is controlled in response to the venturi vacuum force within the chamber 16 and the manifold vacuum force within the chamber 21.

When the vehicle speed exceeds the predetermined one, the solenoid 27 is energized by way of the electric signals from the conventional governor. This changes over the solenoid valve 24 as shown in FIG. 3; now the conduit 25 is connected to the conduit 23 and the chamber 21 is vented to the atmosphere. Consequently, returning force of the spring 32 displaces the two diaphragm members 17 and 19 and the chamber 16 integrally to the position shown in FIG. 3. The throttle valve 12 is thus conditioned to its closed position. As the second throttle valve 12 is being closed off, the venturi vacuum force to the chamber 16 from the secondary induction passage 11 decreases. This further closes slightly the secondary throttle valve 12 by way of the spring 26.

The vehicle speed goes down below the predetermined value when the secondary throttle 12 is closed. And the solenoid 27 is de-energized to change-over the solenoid valve 24 to the condition shown in FIG. 2. Consequently, first the chamber 21 is connected to the manifold vacuum and the two diaphragm members 17 and 19 and the chamber 16 are displaced integrally to the position as shown in FIG. 2 to open the secondary throttle valve 12. As the secondary throttle 12 is being opened again, the venturi vacuum force into the chamber 16 from the secondary induction passage 11 increases. This accelerates slightly opening of the secondary throttle 12.

In the above-described embodiment of the present invention, the manifold vacuum force flow into the chamber 21 is blocked and the atmosphere is supplied to the chamber 21 by way of the energization of the solenoid valve 24 so that the secondary throttle valve 12 is closed. However, the same good effects can maintained by means of a solenoid operated valve 24a which connects the chamber 21 with the atmosphere while the manifold vacuum force is supplied into the chamber 21 as shown well in FIG. 4.

Although certain specific embodiments of the invention have been shown and described, it is obvious that many modifications thereof are possible. The invention, therefore, is not intended to be restricted to the exact showing of the drawings and description thereof, but is considered to include reasonable and obvious equivalents.

What is claimed is:

1. A governing apparatus for a double barrel compound type carburetor having primary and secondary induction passages, throttle valve in each of said passages and a mechanism for opening the primary throttle valve, comprising servo means for controlling the secondary throttle valve in accordance with venturi vacuum force produced at least within said primary induction passage and a vacuum source communicated therein, said servo means including a casing, a first and second diaphragm members clamped within said casing for forming a first, second and third chambers, said third chamber being normally connected to said vacuum source, a link device connected to said first diaphragm member for controlling opening degree of said secondary throttle valve and a first and second springs respectively. installed within said second and third chambers to normally bias said link device to urge said secondary throttle valve in a closing direction, said first spring having a larger biasing force than that of said second spring; first conduit means for connecting said first chamber constantly with the atmosphere; second conduit means for bleeding said second chamber into a venturi in said primary induction passage; means for selectively connecting said third chamber to the atmosphere when vehicle speed exceeds a predetermined value; and a vehicle speed responsive governor for regulating said means.

2. A governing apparatus for a double barrel compound type carburetor as set forth in claim 1, wherein said servo means controls said secondary throttle valve in accordance with venturi vacuum force produced within both of said primary and secondary induction passages and said vacuum source communicated therein, and said second conduit means is provided with a pair of vacuum bleeder opening into both of said primary and secondary induction passages.

3. A governing apparatus for a double barrel compound type carburetor as set forth in claim 1, wherein said second diaphragm member is provided with a stopper member which is urged onto the inner wall of said casing while said third chamber is connected to said vacuum source.

4. A governing apparatus for a double barrel compound type carburetor as set forth in claim 1, wherein said means for selectively connecting said third chamber to the atmosphere comprises valve means for cutting off the communication of said third chamber with said vacuum source and leading the atmosphere into said third chamber when the vehicle speed exceeds the predetermined value.

5. A governing apparatus for a double barrel compound type carburetor as set forth in claim 4, wherein said valve means comprises a solenoid operated valve, said valve being operated to lead the atmosphere into said third chamber by way of the solenoid energized by electric signals from said governor when the vehicle speed exceeds the predetermined value.

6. A governing apparatus for a double barrel compound type carburetor as set forth in claim 1, wherein said third chamber is provided with conduit means in constant communication with said vacuum source and said means for selectively connecting said third chamber to the atmosphere comprises valve means for leading the atmosphere into said third chamber when the vehicle speed exceeds the predetermined value.

7. A governing apparatus for a double barrel compound type carburetor as set forth in claim 1, wherein said first conduit means connect said first chamber with an upper portion of said secondary induction passage and includes a branch conduit in connection with said means.

8. A governing apparatus for a double barrel compound type carburetor as set forth in claim 1, wherein engine manifold vacuum force is adapted for said vacuum source.

t i =0: a: a: 

1. A governing apparatus for a double barrel compound type carburetor having primary and secondary induction passages, throttle valve in each of said passages and a mechanism for opening the primary throttle valve, comprising servo means for controlling the secondary throttle valve in accordance with venturi vacuum force produced at least within said primary induction passage and a vacuum source communicated therein, said servo means including a casing, a first and second diaphragm members clamped within said casing for forming a first, second and third chambers, said third chamber being normally connected to said vacuum source, a link device connected to said first diaphragm member for controlling opening degree of said secondary throttle valve and a first and second springs respectively installed within said second and third chambers to normally bias said link device to urge said secondary throttle valve in a closing direction, said first spring having a larger biasing force than that of said second spring; first conduit means for connecting said first chamber constantly with the atmosphere; second conduit means for bleeding said second chamber into a venturi in said primary induction passage; means for selectively connecting said third chamber to the atmosphere when vehicle speed exceeds a predetermined value; and a vehicle speed responsive governor for regulating Said means.
 2. A governing apparatus for a double barrel compound type carburetor as set forth in claim 1, wherein said servo means controls said secondary throttle valve in accordance with venturi vacuum force produced within both of said primary and secondary induction passages and said vacuum source communicated therein, and said second conduit means is provided with a pair of vacuum bleeder opening into both of said primary and secondary induction passages.
 3. A governing apparatus for a double barrel compound type carburetor as set forth in claim 1, wherein said second diaphragm member is provided with a stopper member which is urged onto the inner wall of said casing while said third chamber is connected to said vacuum source.
 4. A governing apparatus for a double barrel compound type carburetor as set forth in claim 1, wherein said means for selectively connecting said third chamber to the atmosphere comprises valve means for cutting off the communication of said third chamber with said vacuum source and leading the atmosphere into said third chamber when the vehicle speed exceeds the predetermined value.
 5. A governing apparatus for a double barrel compound type carburetor as set forth in claim 4, wherein said valve means comprises a solenoid operated valve, said valve being operated to lead the atmosphere into said third chamber by way of the solenoid energized by electric signals from said governor when the vehicle speed exceeds the predetermined value.
 6. A governing apparatus for a double barrel compound type carburetor as set forth in claim 1, wherein said third chamber is provided with conduit means in constant communication with said vacuum source and said means for selectively connecting said third chamber to the atmosphere comprises valve means for leading the atmosphere into said third chamber when the vehicle speed exceeds the predetermined value.
 7. A governing apparatus for a double barrel compound type carburetor as set forth in claim 1, wherein said first conduit means connect said first chamber with an upper portion of said secondary induction passage and includes a branch conduit in connection with said means.
 8. A governing apparatus for a double barrel compound type carburetor as set forth in claim 1, wherein engine manifold vacuum force is adapted for said vacuum source. 